(1) Field of the Invention:
The present invention relates to a gas-discharge display panel for displaying a color picture, comprising plural gas-discharge cells arranged in a matrix, respective discharge spaces which are enclosed by a transparent front plate and a rear plate and respective fluorescent layers which are deposited on an inner surface of those plates. More particularly, the invention relates to the improvement effected by raising radiation efficiency and simplifying and facilitating manufacture of the display panel.
The present invention further relates to a high definition type gas-discharge display panel comprising plural gas cells which are simply constructed such that large plate size and high radiation efficiency are facilitated.
(2) Description of the Background Art:
Conventional direct current type gas-discharge display panels of various kinds, including one memory type, have an advantage such that high radiation efficiency, for instance on the order of approximately 0.3%, can be attained by utilizing a positive column generated by a gas discharge. At the same time, the radiation time duration can be elongated by providing a memory function or the like, so as to further increase the brightness of a displayed picture. However, in these prior displays the discharge path is required to be elongated so as to generate the positive column. The display must therefore be provided with a cell sheet for keeping inner surfaces of the front and the rear plates away from each other so as to elongate the discharge path thereof. Further, these displays require using a production technique for depositing fluorescent material, which is customarily called "phosphor", on an inner surface of an elongated hole provided through the cell sheet as the discharge space of the cell. Consequently, the gas-discharge cell of this kind has various disadvantages including difficulty of manufacture resulting in lack of mass-producibility and the expensive production.
Another kind of gas-discharge cell utilizing negative glow has been substantially deserted for displaying a color picture because of low radiation efficiency on the order of 0.02%, and further has a serious defect of lack of practical usability because of the unstable gas discharge being driven by a small discharge current.
Meanwhile, high definition type gas-discharge display panels of various kinds are under development to attain large size, high efficiency and further high definition. Among these display panels, a two-plate type gas-discharge panel formed, roughly speaking, of a transparent front insulation plate and a rear insulation plate has been adapted as the most suitable for the above mentioned development.
FIGS. 1a and 1b show a typical conventional structure of the gas-discharge display panel of this two-plate type. FIG. 1(a) is a cross-section showing a portion thereof and FIG. 1(b) is a plan view from the viewer side of the panel as shown in FIG. 1(a).
The conventional panel as shown in FIGS. 1(a) and (b) is formed of two plates comprising a transparent front glass plate FG and a rear insulation plate RG. An inner surface of the front glass plate FG is formed with plural triangular elongated grooves in parallel with one another. A display anode DA is disposed on a bottom of each of these grooves, while a shading layer LS is disposed on each of the flat portions of these grooves. On every other one of the grooves, a scanning anode SA operating as an auxiliary anode to be described later is disposed. In addition, fluorescent layers Ph of red (R), green (G) and blue (B) respectively are disposed separately on inclined side-walls of these grooves. Plural elongated cathodes DC are disposed in parallel on an inner surface of the rear insulation plate RG formed, for instance, of glass.
This conventional gas-discharge display panel of the two-plate type is operated such that the fluorescent layers Ph disposed on the inclined walls of the grooves formed in the inner side of the transparent front plate FG are brightened under the excitation of ultra-violet rays emitted from the gas-discharge generated between the display anode DA and the cathode DC. Hence, the brightened fluorescent layers Ph are viewed through the transparent front plate FG by a viewer. The scanning of this gas-discharge display panel is effected by priming discharges successively generated between the plural scanning anodes SA and the plural cathode DC. A voltage or a current is applied in response to an amplitude of a picture signal to be displayed between the cathode DC and the display anode DA positioned in the vicinity of the generated priming discharge, so as to emit the aforesaid exciting ultra-violet rays.
However, this conventional gas-discharge display panel of two-plate type has the serious defect of contamination of displayed colors due to the inferior segregation between discharge cells.
FIG. 2 shows another conventional structure of a gas-discharge display panel of three-plate type.
This conventional structure is of three-plate type comprises a cell sheet CS inserted between the front plate FG (not shown) and the rear plate RG. The cell sheet CS is provided with plural cylindrical cell holes therethrough, on inner walls of which fluorescent layers Ph in red (R), green (G) and blue (B) are applied in required cyclic order. The elongated display anode DA and the elongated cathode DC are disposed on the inner surfaces of the rear plate RG and the front plate FG respectively and cross each other at positions corresponding to the cylindrical cell holes. The elongated auxiliary scanning anode SA is disposed at bottoms of elongated recesses formed in the cell sheet CS in parallel with and midway between rows of cell holes.
This conventional display panel has superior segregation between discharge cells and high radiation efficiency because of the non-transmission type of view and because of the positive utilization of the positive column presenting excellent radiation efficiency of ultraviolet rays. However, this conventional display panel has production difficulty in application of fluorescent layers on the inner walls of the narrow cylindrical cell holes, which results in reduced possibility of industrial mass-production.